Ferromagnetic alloys are well known and have had wide use throughout industry. One area where ferromagnetic alloys are receiving particular attention is in the field of electronic article surveillance (EAS) as disclosed by P. A. Picard in French patent no. 763,681 (1934). Generally, certain ferromagnetic alloys exhibit high magnetic permeability and low coercivity thereby making their use as an EAS marker attractive. In the past, it was suggested to use ferromagnetic strips or wires sandwiched between two attached layers of dielectric material to form markers that can be detected in a magnetic field as described in U.S. Pat. Nos. 4,581,524 and 4,568,921, respectively. U.S. Pat. No. 3,856,513 describes various amorphous alloys and methods for making the same. Although prior amorphous alloys have worked well, it would be advantageous to have amorphous materials that have properties that lend themselves to use in an EAS marker and are easy to fabricate and detect. One characteristic that is sought is near zero magnetostriction which is associated with high magnetic permeability. Although there are ferromagnetic alloys that demonstrate near zero magnetostriction, these alloys suffer an excessive dependence on the frequency of the applied field which means the range of frequency in which EAS markers can be detected is greatly reduced.
Another problem with prior amorphous ferromagnetic alloys of high magnetic permeability has been the need in their composition of a high quantity of cobalt, which is a strategic, expensive material, in their composition.
One advantageous form of ferromagnetic material is that of a fiber as disclosed in co-pending patent application no. 290,547. It had been found that ferromagnetic alloys in the form of fibers can be randomly oriented and still be detectable. What has been determined, however, is that the signal from such oriented fibers have a signal degradation relative to the amount of material.